Planters are known to be useful as equipment for sowing crops on a field and other agricultural applications. Planters are often needed for large-scale farming operations. Conventional planters have bins arranged in one or more rows for dispensing seeds or fertilizer as the planter is towed behind a tractor. The most common spacing for rows in the United States is 30 inches apart, and the planter units can provide precision sowing according to the type of seed to be sown and the rate at which the seeds are to be sown. Some planters have now been developed which allow for a single planter to be adjusted to multiple row spacings. For example, a single planter may provide a first configuration of planter units having 30-inch spacing, a second configuration of planter units having 20-inch spacing, and a third configuration of planter units having 70-centimeter (27.55 inch) spacing. While both conventional and variable-spacing planters may be useful in some instances, there are still numerous deficiencies with existing planter approaches and there remains the potential for more useful planters and planter accessories for the modern farming industry.